Investors failed to bite on King Digital Entertainment’s stock during the first day of trading Wednesday, as the maker of the smash hit mobile app Candy Crush saw its share prices drop 9% by 10:30 to around $20.50.

King Digital had raised $500 million before Wednesday by pricing its stock at $22.50 a share, valuing the company at $7 billion—one of the biggest IPOs so far this year, reports the New York Times. The stock began trading on the New York Stock Exchange Wednesday.

Candy Crush Saga attracts nearly 100 million active users every day, leading to enormous profits for the company. Its earnings bounced 7,000 percent from the same time a year ago to nearly $568 million in 2013.

But some question whether King Digital isn’t just a one-trick pony riding the success of Candy Crush. “Companies like King are reliant on hits,” Mark Little, an analyst at the technology consultant Ovum in London told the Times. “It’s an open question whether they can sustain their success.”